It is certainly, and helpfully, true that as you age, you care less and less about what other people think. My older relatives often said that to me when I was young and I did not quite believe them at the time but now I do.
This piece also reminded me of a late evening spent drinking beer with an economist friend in one of the student bars in Madison during the Institute for Research on Poverty summer research conference. I have never felt as completely invisible in my whole life as I did that night. As far as the drunken Badger undergrads were concerned, we were just not there. I like to think that our being invisible made our amateur ethnographic observations more credible.
Hat tip: Kim Ross